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25 December 2022, Volume 17 Issue 6
    

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    Original Article
  • LIU Bin1,2, YAO Qiufeng1, ZHAO Ping1, REN Hao1, QI Zhongtian1, QIN Zhaoling1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 337-346. https://doi.org/10.3969/j.issn.1673-6184.2022.06.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Zika virus (ZIKV) is a kind of mosquito-borne pathogen. Its infection can cause Zika virus disease. There is currently no specific treatment. Autophagy is a process in which cells maintain their own homeostasis and promote the reuse of intracellular substances and energy, but it is often hijacked by some viruses to promote their own replication. In this study, human hepatoma cell line (Huh7) was used as the target cell, and the mTagRFP-mWasabi-LC3 dual fluorescent reporter system was used to detect the formation of autophagosomes. Western blotting was used to detect the expression of autophagy markers LC3 and P62 proteins after ZIKV infection at different time points. Cells were pretreated with autophagy inhibitors (wortmannin and chloroquine), Beclin-1 specific short hairpin RNA (shRNA) and autophagy inducer rapamycin. Then their effects on viral protein expression and extracellular progeny virus titer were detected by Western blotting and virus plaque assay. The signaling pathways involved in the regulation of autophagy in ZIKV infection were detected by Western blotting. The results showed that the number of LC3-positive autophagosomes increased significantly in Huh7 cells after infection by ZIKV. The expression of LC3-II increased significantly from 12 h post infection, and P62 protein was significantly down-regulated at 48 h post infection. Both autophagy inhibitor treatments and interference of Beclin-1 expression could effectively inhibited ZIKV infection and the production of progeny viruses. Rapamycin treatment increased the content of extracellular progeny viruses (P<0.05). ZIKV infection enhanced the phosphorylation of adenosine 5’-monophosphate-activated protein kinase (AMPK) and TSC2, and reduced the phosphorylation of mammalian target of rapamycin (mTOR). The results demonstrate that ZIKV infection induces autophagy by activating the AMPK/TSC2/mTOR signaling pathway in Huh7 cells, and utilizes autophagy to promote virus replication and progeny virus production. It provides theoretical and experimental basis for the development of anti-ZIKV drugs based on autophagy-related molecules.
  • TANG Yijie1, WU Min1, LU Wei1, FENG Yanling1, YUAN Zhenghong2, ZHANG Xiaonan1,3, ZHANG Zhanqing1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 347-359. https://doi.org/10.3969/j.issn.1673-6184.2022.06.002
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    The formation of immune complexes is considered to be one of the important causes of inflammatory injury during virus infection. Quantification of immune complexes in virus-infected patients can help monitor disease progression and understand virus-host interactions. In this study, a solid-phase C1q-binding fluorescence immunoassay method quantifying circulating immune complexes (CICs) based on published reports was optimized. Using complement molecule C1q for capturing the immune complexes, and fluorescent-labeled goat anti-human IgG for readout, the clinical significance of CICs in 220 chronic hepatitis B (CHB) patients, 20 non-hepatitisB virus (HBV) hepatitis patients, 20 healthy controls, and 10 individuals recovered from CHB were explored. The results showed that about 97% of CHB patients had elevated CIC levels, which were significantly positively correlated with virological indicators HBV surface antigen (HBsAg) (r=0.197 3, P=0.005 8) and HBV DNA (r=0.217 8,P=0.002 3). More importantly, CIC levels were positively correlated with liver injury-related biochemical indicators alanine aminotransferase (ALT) (r=0.158 0, P=0.020 0) and aspartate aminotransferase (AST) (r=0.151 3, P=0.035 3), while was negatively correlated with complement C4 (r=-0.210 0, P=0.003 0). The levels of CICs and complements showed significant differences among the patients with different levels of inflammation and fibrosis, and their levels fluctuated correspondingly with clinical stages of CHB. Among the patients in immune tolerance and low replication stages, the content of CICs was lower and the serum complement level was elevated. But, the results were the opposite among the patients in immune active stage and HBV e antigen (HBeAg)-negative hepatitis. The above results all suggest that there are liver damage and a large consumption of complements caused by the formation of CICs in the blood circulation of CHB patients. The monitoring of CICs can reflect the potential damage of CHB patients to a certain extent.
  • LIU Yuanyuan1, QIN Xiaowen2, CHEN Huaxin2, YU Zhiming2, OU Qinfang2, LIU Qianqian1, XU Yuzhen1, YANG Qinluan1, ZHANG Bingyan1, GAO Yan1, ZHANG Wenhong1, SHAO Lingyun1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 360-365. https://doi.org/10.3969/j.issn.1673-6184.2022.06.003
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    This paper screened and followed up close contacts of active pulmonary tuberculosis to understand the latent infection and morbidity of close contacts and analyze related factors. It retrospectively analyzed the clinical data of patients with active pulmonary tuberculosis hospitalized in the tuberculosis ward of Wuxi No.5 People’s Hospital from March 2012 to August 2019, and analyzed and followed up the close contacts who had conducted the interferon-γ release assay (IGRA). A total of 39 active pulmonary tuberculosis patients under initial treatment and 74 close contacts were included in the analysis. Of all the 74 close contacts, 27 contacts were IGRA positive (36.5%) and 47 contacts were IGRA negative (63.5%). None of the 27 IGRA-positive close contacts progressed to active tuberculosis, but the differences between the two groups in terms of smoking (3/27 vs 0/47, P=0.045), contact time with tuberculosis patients >5 h/d (22/27 vs 23 /47, P=0.007), living in the same house (23/27 vs 20/47, P=0.001) were statistically significant. Active tuberculosis patients corresponding to IGRA-positive close contacts and those corresponding to IGRA-negative close contacts were further compared, respectively, which found that the active TB patients corresponding to the IGRA positive group had more sputum smear tuberculosis bacteria load than that of the IGRA negative group (P=0.019). Multivariate analysis showed that the amount of tuberculosis bacteria in sputum smear of tuberculosis patients was a significant factor influencing IGRA results of their close contacts. Close contacts of active pulmonary tuberculosis with higher sputum tuberculosis load are more likely to be IGRA positive.
  • LIU Minxue, LIANG Jiahui, HUANG Liying, CEN Zhenjiao, WANG Shuangjie, YAN Chenglan
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 366-373. https://doi.org/10.3969/j.issn.1673-6184.2022.06.004
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    The purpose of the current study is to analyze the pathogens of otitis in children and its drug sensitivity for references of clinical empirical medication. In this retrospective study, we analyzed ear secretion culture data of the children with otitis in the Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from January 2019 to December 2021. We calculated the constituent ratio of the positive bacteria and fungi, then analyzed the drug sensitivity of the major Gram-positive bacteria, Gram-negative bacteria and candida. The results demonstrated that, of all the 918 ear secretion samples, 623 were positive culture. 438 (70.30%) were bacteria positive, and 164 (26.32%) were fungi positive, while 21 (3.37%) were both bacteria and fungi positive. Staphylococcus aureus and Streptococcus pneumoniae were the major gram-positive bacteria, and Pseudomonas aeruginosa and Haemophilus influenzae were the major gram-negative bacteria. The most common yeast fungi were Candida parapsilosis and Candida albicans, and the top two mould were Aspergillus flavus and Aspergillus niger. As results of drug sensitivity test of main gram-positive bacteria, Staphylococcus aureus were sensitive to vancomycin, linezolid, aminoglycosides and quinolones, but showed high resistance to penicillin and macrolides. However, most Streptococcus pneumoniae were sensitive to penicillin, vancomycin, levofloxacin and amoxicillin-clavulanic acid, but were highly resistant to macrolides and the second generation cephalosporins. In terms of major gram-negative bacteria, Pseudomonas aeruginosa were widely sensitive to penicillins, cephalosporins, quinolones and carbapenems agents. And, all Haemophilus influenzae in the study were sensitive to amoxicillin-clavulanic and ofloxacin, but a part of strains were resistant to sulfamethoxazole, ampicillin and the second generation cephalosporins. Antifungal drug sensitivity results showed that all isolated Candida parapsilosis and a large part of Candida albicans were sensitive to triazole drugs. It concludes that the top three pathogenic bacteria of otitis in children are Staphylococcus aureus, Streptococcus pneumoniae and Pseudomonas aeruginosa. In terms of pathogenic fungi, the major yeast and mould are Candida parapsilosis and Aspergillus flavus, respectively. Clinicians could empirically administrate antibiotics or antifungal agents referring to our study results before getting culture and drug sensitivity reports.
  • Case Analysis
  • MIN Yan1, WU Jing1, LI Jixia1, GONG Yanwen2,HU Chengjin1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 374-379. https://doi.org/10.3969/j.issn.1673-6184.2022.06.005
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    In the sputum culture of a patient with tracheotomy, we found a kind of Gram-negative bacteria with membrane growth, which was not identified by Vitek2 Compact. Then, the strain was identified by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and 16S ribosomal RNA (16S rRNA) sequencing, and the results showed that the strain was Kerstersia gyiorum. Kerstersia gyiorum is a kind of Gram-negative non-fermenting bacterium. A few of foreign cases reported that this bacterium might be a conditional pathogen, which could be isolated from sputum and alveolar lavage fluid of tracheotomy patients, and from urine of percutaneous fistula patients. This bacterium could also cause bacteremia and participate in the occurrence and development of chronic otitis media. Chinese literature on the isolation of Kerstersia gyiorum is rare. The strain of the bacterium was isolated, and the basic characteristics of the bacterium were reported as follows to enable clinical microbial laboratory personnel to strengthen the understanding and attention on it.
  • WANG Chongzhen1, WEI Haodong2, ZHU Xiong1, WANG Licheng1, LI Huan1, FU Xiaoying1, LI Yuanli1, CHEN Dongke1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 380-385. https://doi.org/10.3969/j.issn.1673-6184.2022.06.006
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    The present paper reported a case of corneal ulcer caused by Lasiodiplodia theobromae. The male patient was 54 years old. His right eye became red and the pain increased for 3 days. Ophthalmic examination showed mixed hyperemia in the bulbar conjunctiva of the right eye. The whole cornea was gray and cloudy, representing an uneven surface like a map. Light white deposition could be seen below the anterior chamber, and the remaining conditions in the eye were not clear. Corneal curettage specimens were taken for fungal fluorescence staining and culture. The cultured strains were identified by morphology and molecular biology. The drug sensitivity of filamentous fungi was tested by E-test. Septahypha can be seen under fluorescent staining of fungi. After incubation for 14 days, conidia could be seen in the conidiophores. The pathogen was identified as Lasiodiplodia theobromae by sequencing. Drug susceptibility result showed that amphotericin B and voriconazole were relatively sensitive.The corneal ulcer was confirmed to be caused by Lasiodiplodia theobromae. The right eye was treated with fluconazole eye drops q2h, and the fluconazole sodium chloride injection was used with 0.4 g qd via intervenous drop infusion. The patient did not get better after 5 days of treatment and asked to be discharged.
  • Review
  • SUN Jian1,2, ZHANG Jiming1,3,4
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 386-394. https://doi.org/10.3969/j.issn.1673-6184.2022.06.007
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    Myeloid-derived suppressor cells (MDSCs) are a population of myeloid-derived cells with specific markers and immunosuppressive functions. MDSCs can enrich under pathological conditions (e.g., advanced cancer, sepsis, and chronic infection) and suppress the proliferation, activation, and migration of T lymphocytes and other immune cells. The frequencies of MDSCs are significantly associated with disease development and patient outcomes. Through new detection methods including single cell sequencing and mass spectrometry, researchers have found significant differences in phenotypic markers, genetic expression, metabolism, and regulatory pathways between MDSCs and normal myeloid cells. Abundant achievements have been also obtained on therapies targeting MDSCs especially in cancer research. In this review, we start with milestones in MDSCs research, focus on the mechanisms of therapies targeting MDSCs and their roles in infectious diseases, and summarize recent achievements in MDSCs research.
  • WANG Huanru1, TENG Zheng1, SHI Qi2, ZHANG Xi1
    JOURNAL OF MICROBES AND INFECTIONS. 2022, 17(6): 395-400. https://doi.org/10.3969/j.issn.1673-6184.2022.06.008
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    Creutzfeldt-Jakob disease(CJD) is the most common prion disease in human beings. Due to the infectivity and 100% fatality rate of CJD, early diagnosis is critical for disease control and prevention. Diagnosis of CJD needs combined analysis of both clinical features and laboratory testing results. The current review mainly focuses on the laboratory testing technologies of CJD including direct and indirect tests of prion, detection of the disease markers, as well as the analysis of disease-related gene PRNP, aiming to provide technical references for the normalization and development of CJD laboratory testing.